Method and apparatus for determining the volume of articles



Dec. 15, 1953 L. WEINER ETAL METHOD AND APPARATUS FOR DETERMINING THE VOLUME OF ARTICLES Filed Feb. 9, 1949 1.. 1". Wag 2 1 8Y6. p. Zak/740p llll ?atented Dec. 15, 1953 STATES TENT .21;

METHOD AND APPARATUS FOR DETERMEN- ENG THE VOLUME 0F ARTICLES Louis I. Weiner, Philadelphia, and Benjamin Paul Berman, Upper Darby, Pa.

(Granted under Title 35, U. S. Code (1952),

sec. 266) 17 Claims.

The invention described herein, if patented, may be manufactured and used by or for the Government for governmental purposes without the payment to us of any royalty the con.

This invention relates to methods and apparatus for determining the volume or" an article, especially a porous textile article such as a glove, mitten, sock, or knitted cap or a fabric bag, which is subject to shrinkage when washed. By accurately measuring the volume or" a textile article before and after washing, the amount and percentage of shrinkage are easily calculated. Accurate knowledge of the shrinkage of diiierent articles may be or considerable value to purchasers of textile goods in large volume.

The prior art includes a number of publications and patents having some bearing on the subject-matter of this invention. Patent No. 2,074,832 dated March 23, 1937, for example, discloses apparatus for measurin the capacity or volume of animal intestines which are later to be employed as sausage casings, the measuring method depending on the retention of air in the casing itself. In the Rayon Textile Monthly for liebruary and March 1937, an articl entitled Test Methods for Womens Washable Cotton and Rayon Gloves by Richard S. Cleveland of the National Bureau of Standards describes methods of determining percentages of shrinnage of womens washable cotton and rayon gloves. measurements of socks have been made for some time on the Schiefer sock measuring device, described in Federal Standard Stock Catalog, section IV (part 5), GCC L lQIa, Supplement, October 8, 19%. The S-chiefer method and apparatus are criticized in an article entitled The Measurement of Shrinkage in Socks by the Schiefer Measuring Device by G. Smith in The Journal of the Textile Institute for April 1943.

In accordance with our invention, the article whose volume is to be measured is clamped on a form carrying a vesicle or bladder of gas-impervious thin-walled material (e. g., somewhat larger than the largest article intended to be measured, in which case the bladder need not be elastic), and a bell jar or other casing is placed over the form and article and then sealed to hold air pressure. The bladder is then inflated with compressed air to subject the article to a predetermined internal pressure, after which the pressure in the bell jar is built up to a predetermined superatmospheric pressure which is higher than the internal pressure in the bladder. The air pressure in the bladder is increased to a point substantially equal to the pressure in the bell jar,

Shrinkage in order to prevent distortion of the volume of the bladder and article by reason of compression thereof that otherwise would be caused by the superatmospheric pressure in the bell jar. Then the air in the bladder is vented to the atmosphere, and the pressure in the bell jar is noted. on a manometer or other pressure measuring device. The difference in pressures within the bell jar, if calibrated, will give the volume of the bladder when blown up to fill the article, which is substantially the internal volume of the article itself. Then if desired the article is washed one or more times, and its new volume is measured by the same process. The difference in the two volumes is the shrinkage volume which may be expressed in percentage of the original volume.

In the accompanying drawings forming a part of this specification,

Fig. 1 is a diagram of the apparatus, omitting the article to be measured and the bladder and clamps;

Fig. 2 is a fragmentary view in vertical section showing the bladder clamped on the form;

Fig. 3 is a vertical section showing the bell jar clamped and sealed on the table, and the article to be measured distended by the blown up bladder within it.

Referring particularly to the drawings, first to the diagram, Fig. 1, a table or other flat support it has a bell jar l2 removably supported thereon. The bell jar may be of glass or a transparent plastic, with edges so formed as to make a sealing engagement with the table. To the table or support an upright form It is by means not shown. The form hollow to receive an air pipe is (which extends below the table and outside to a connection with a source of com pressed air, as will be described) and has one or more outlets it: to permit discharge oi air from pipe it into the interior of an article supported on form it. Another pipe It extends from the interior of the bell jar to a T connection ll in a compressed air line HS which has a valve it to control discharge from the same and an inlet valve 20 to control inflow of compressed air. Preferably the air line it has a connection with a tank or other source of compressed air whose pressure is automatically controlled by known means to be maintained in excess of 159 mm. above standard atmospheric pressure (760 mm. at sea level) that is, in excess of 910 mm. A pair of manometers ii, 22 are supported within convenient distance of the bell jar, and each has an upper end received in a reservoir 26, which permits the recovery of any mercury 23 which may be blown out of the manometers by excessive air pressures. Manometer 2| is coupled by a T 2'! with the compressed air line l8, on the pressure side of discharge valve l9. Manometer 22 is directly connected with air line M. A pipe 28 is coupled by a T 29 to air line I8 and by another T 30 to manometer 22. A valve 3| controls flow through pipe 28 and a venting valve or cock 32 permits pressure within pipe 28 and air line M to be lowered to atmospheric pressure. T 29 is of course coupled at a point between valve 20 and a cut-off valve 33 in the compressed air line l8 in advance of the T H.

Now referring to Fig. 2, the form I3 is shown with a rubber or plastic vesicle or bladder 35 fitted thereon and sealingly clamped thereto by a clamp 36. Thus the bladder may be blown up if compressed air is permitted to flow through air line 14.

Referring to Fig. 3, a sock 40 is shown as it would appear if subjected to a measuring operation on the described apparatus. The sock 43 envelops the rubber bladder 35 and is clamped upon the form l3 at its base by means of a clamp 4|. As the bladder is blown up it fills the sock as illustrated and distends it to the maximum extent permitted by the knitting or weavin of the sock.

Operation First, valve 20 is closed, and valves 3|, 32, 33 and I9 are opened. The system is then at atmospheric pressure, which may be read on either manometer. The vesicle or bladder 35 is then placed around the form l3 and clamped, and the sock 43 or other article of apparel is drawn over the clamped bladder and is in turn clamped as at 4|. The bell jar is then positioned over the table and clamped and sealed. A clamp 42 including a pivoted frame may be employed to thrust the lower edges of the bell jar into sealing engagement with a gasket 43 fixed to the table. Then valves I9, 32 and 33 are closed, valve 3| remaining open, and compressed air is admitted to the system by opening valve 20. The operator will keep valve 20 open until manometer 22 registers (let us say) 20 mm. of mercury above atmospheric pressure, whereupon valve 20 will be closed to hold that pressure. The compressed air will fill the bladder and distend the sock, which will then appear as in Fig. 3.

Now valves 3| and I9 are closed and valves 33 and 20 are opened. This will permit air pressure to build up within the bell jar outside of the bladder-distended sock. When such pressure has been built up to (let us say) 150 mm. above the atmospheric pressure, as read on manometer 2|, valves 20 and 33 are closed. Valves 20 and 3| are then reopened, which admits additional compressed air to bladder 35, until the pressure therein is substantially equal to the superatmospheric pressure in bell jar I2 (as determined by substantially equal readings of manometers 2| and 22), at which point valves 2|! and 3| are closed. Next valve cock 32 is opened to vent air in the bladder to the atmosphere and another reading taken on manometer 2|. The difference between the first and the second readings on manometer 2|, when calibrated, will give the volume of the bladder when blown up to fill the sock. Valve I9 is now opened to vent the air in the bell jar external to the bladder. Now the bell jar is removed and the sock being tested may be removed and washed one or more times, and then replaced on the form for a repetition of the measurement of its volume. The difference in the two volumes is the volume of shrinkage, Which may be expressed in percent of the original volume.

In an actual test at the Quartermaster Research and Development Laboratories, Philadelphia, Pennsylvania, the following readings and results were obtained:

13659.0X807.7 SE1: 13659.0

. 2094.41829.0 Percent shrinkage Percent shrinkage= The formula used in the above computation can be greatly simplified, particularly when the apparatus is not used for comparative measurements, but simply for volumetric measurement of a gas-permeable collapsible article. This simplified formula can be represented as follows:

VXP P.-

wherein v is the volume of the article, V is the predetermined internal volume of the bell jar, PI is the absolute pressure in the bell jar when the bladder is collapsed, and Pi is the absolute pressure in the bell jar when the bladder is expanded. In this formula the value of VUB (volume occupied by upright form and empty bladder) is neglected, provided upright form I3 is designed with a comparatively small diameter (as shown in Fig. 2 of the drawings); on the other hand, if upright form |3 has a comparatively large diameter, and/or high accuracy of the measurement is of the essence, the VUB value has to be added to the result as outlined in the calculations set forth in the preceding table.

While it is customary to employ an initial pressure of mm. above atmospheric, other values may be used. It should be stated that the relationship or proportion of the volume of the bell jar to that of the sock or other article under test will afiect the accuracy of the method, since the larger the proportionate size of the bell jar the less the pressure change when the bladder is collapsed by venting to the atmosphere, and the lower the degree of accuracy.

The invention is not limited to use with the articles mentioned. Many hollow articles incapable or" holding air under pressure because of perforations or porous walls may have their volumes measured by the described method. In the case of a mitten or glove, modification of the bladder may be most desirable to permit it when blown up to fill all the fingers. Slight modifications of the clamping devices will be necessary to suit different shapes of articles, and of course the form itself may have a shape complementary to the article being measured.

If preferable, a gas other than air may inflate the bladder and surround the distended and collapsed article during the readings, but normally air will be used. All the readings taken during a measurement will be taken with the temperature of the gas constant.

It is felt that the described method has certain advantages over the known prior art. According to the invention, many porous or perforated articles may be measured for volume, whether or not shrinkage is to be determined. In other words, the invention makes it possible to measure the volume of an article which is incapable of holding a gas under pressure, by merely taking pressure readings after positioning the article and manipulating the valves. If the necessary corrections are made for variations in temperature and changes in the shape or the form and the size of the bladder, more accurate results are possi is than if many tedious tape measurements are taken.

Having described our invention, what we claim as new and desire to secure by Letters Patent is:

1. A method of determining the volume of an article incapable of holding a gas under pressure, which comprises placing the article over a distendable sealed body capable of holding a gas under pressure, securing the article, blowing up the distendable body with a gas, surrounding the article filled with the distended body with a confined body of the gas under pressure greater than the pressure within the distended body, taking a reading of pressure of the gas surrounding the filled article, increasing the gas pressure within said distendable body until it is substantially equal to the pressure of the gas surrounding the vented article, causing the compressed gas within the filled article to leave the distended body, taking a reading of the changed pressure of the gas surrounding the article, and finally computing the volume of the article.

2. A method of determining the volume of an article incapable of holding air under pressure, which comprises blowing up the article with a bladder fitting inside the article by means of air under super-atmospheric pressure, surrounding the blown up article with a confined body of air under pressure greater than the pressure within the filled article, taking a reading of the pressure of the air surrounding the blown up article, increasing the air pressure within said bladder until it is substantially equal to the pressure of the air surrounding the blown up article, deflating the article by causing the air therein to exhaust to the atmosphere, taking a reading of the changed pressure of the confined air surrounding the article, and finally computing the 1 volume of the article.

3. Apparatus for determining the volume of an article comprising a support, a form fixed on the support, a source of compressed air connected with the form, a bladder fixed to the form so as to be blown up by said compressed air, a pressure measuring device coupled to the bladder so as to give readings of its internal pressure, means to clamp an article in enveloping relation to the bladder, meam providing a sealed chamber surrounding the clamped article, a pressure measuring device coupled to the sealed chamber, means coupling the sealed chamber with the source of compressed air, a vent to control escape of compressed air from the interior of the bladder, and

valves to control flow of air into and. out of the system.

4. Apparatus for determining the volume of an article comprising a support, a form fixed on the support, a chamber surrounding the form and removably secured upon the support, means to seal the chamber when so secured, a bladder detachably fixed to the form, means to conduct compressed air to and from the interior of the bladder when so fixed, a pressure measuring device coupled to the bladder so as to give readings of its internal pressure, means to clamp an article in enveloping relation to the bladder, means to conduct compressed air to and from the interior of the chamber, a source of compressed air to which both the means to conduct compressed air are connected, and valves to control flow of air into and out of the system.

5. Apparatus for determining the volume of a generally hollow and porous article consisting of a support, a chamber removably mounted on the support, means to seal the lower edges of the chamber against said support, a clamp to hold the chamber sealed on the support when subjected to internal pressure, a hollow form fixed to the support within the chamber, a conduit connected to the interior of the form, a source of compressed air, a vent in said conduit, a valve to admit compressed air to the conduit or to cut off the compressed air permit venting of the air in the conduit, a bladder, means to clamp the bladder upon the form so that it may be blown up air conducted through said conduit and will then hold the pressure, a pr ssure measuring device connected with said conduit, a second conduit connected with the interior of the chamber through the support and also connected with said source of compressed air, a valve to control or shut oi? flow of compressed to said second conduit and hence to the chamber, a second pressure measuring device coupled with the interior of the chamber, and another valve to control discharge of from the second conduit the chamber.

6. A device for measuring the volume of hollow bodies comprising a vesicle of membranous resilient deformable material capable of expanding in response to internal pressure substantially to fill the body to be measured, supporting means for said body and vesicle including means to anchor said vesicle within said body, a chamber to isolate said body and the vesicle disposed therein, means to vary the relative internal pressures in said vesicle and chamber selectively to cause said vesicle to expand substantially to fill said body so that the volume of the vesicle corresponds substantially to the optimum volume of said body or to cause said vesicle fully to contract under the influence of a differential pressure in said chamber while the chamber remains sealed, and pressure sensitive means individual to said vesicle and chamber to indicate the pressure therein.

'7. A device for measuring the volume or" hollow bodies comprising a vesicle of membranous rcsilient deformable material capable oi expanding substantially to fill the body to be measured, supporting means for said body and vesicle including means to anchor ve -cle wit in said body, a chamber to isolate said body and the vesicle disposed therein, means for introducing gas under pressure into said vesicle and chamber selectively to build up pressure in said vesicle sufficient to expand the same substantially to fill said body so that the volume of the vesicle cerresponds substantially to the optimum volume of said body or to build up pressure in said chamber in excess of vesicle pressure, means for venting said vesicle and chamber to the atmosphere including means to vent said vesicle while said chamber remains sealed for causing said vesicle to contract to minimum volume under the influence of a differential pressure in said chamber, and pressure sensitive means individual to said vesicle and chamber to indicat the pressure therein.

8. A device for measuring the volume of hollow bodies comprising a vesicle of membranous resilient deformable material capable of expanding substantially to fill the body to be measured, supporting means for said body and vesicle including means to anchor said vesicle within said body, a closed chamber to isolate said body and the vesicle disposed therein, said chamber being internally dimensioned to receive the body expanded to its optimum volume with a minimum of excess space remaining unoccupied, means for introducing gas at a predetermined pressure into said vesicle to expand the same substantially to the optimum volume of said body, means for introducing gas into said chamber at a pressure higher but less than sufficient to cause appreciable contraction of the expanded vesicle, means for venting said vesicle and chamber selectively including means to vent said vesicle while said chamber remains sealed for causing said vesicle to contract fully under the influence of the differential pressure in said chamber, and pressure sensitive means individual to said vesicle and chamber to indicate the pressure therein.

9. A device for measuring the volume of hollow bodies comprising a vesicle of membranous resilient deformable material capable of expanding substantially to fill the body to be measured, supporting means for said body and vesicle including means to anchor said vesicle within said body, a chamber to isolate said body and the vesicle disposed therein, conduits for connecting said vesicle and chamber to a source of air under pressure, manually operable valves to control the flow of air to and from said vesicle and chamber including valves operable selectively to connect said source of air to said vesicle or chamber and to vent the same selectively so that said vesicle may be expanded substantially to fill the body to its normal volume or fully contracted under the influence of the pressure in said chamber while the latter remains sealed, and means individual to said vesicle and chamber to indicate the pressure therein.

10. A method of measuring the volume of an irregularly shaped fluid pervious hollow body which comprises disposing a vesicle of relatively thin walled resilient deformable material in said body, inclosing said body and the vesicle support ed therein in a sealed chamber of known volume, varying the relative internal pressures as between the vesicle and chamber while they are sealed from each other successively to effect an expansion of the vesicle substantially to the optimum volume of said body and a contraction thereof to minimium volume while the chamber is sealed, noting the pressure in said chamber before and after contraction of the vesicle is effected, and then computing the volume of the body from the known and recorded data relative to pressures in the vesicle and chamber and the volume of the chamber by the use of Boyles law.

11. A method of measuring the volume of an irregularly shaped fluid pervious hollow body which comprises raising the pressure in a sealed relatively thin walled resilient deformable vesicle enclosed within the body to be measured sufficiently to expand said vesicle substantially to the optimum volume of the body while the body and vesicle are enclosed in a sealed chamber of fixed volume, raising the pressure in the chamber to a predetermined value above the pressure in the vesicle, increasing the pressure within said vesicle until it is substantially equal to the pressure within said chamber, reducing the pressure in said vesicle While the chamber remains sealed suiiiciently to contract said vesicle to minimum volume, the quantity of gas in said chamber remaining constant while the pressure of said gas decreases, and then by the use of Boyles law computing the volume of the body being measured from the known volume of the chamber and the pressure therein prior to and after contraction of the vesicle.

12. A method of measuring the volume of a shaped fluid pervious hollow body which comprises introducing ir into a sealed vesicle enclosed within the body to be measured at a predetermined pressure above atmospheric sufficient to expand said vesicle substantially to the normal volume of said body while the body and vesicle are enclosed in a sealed chamber of fixed volume, introducing air into said chamber while the vesicle remains sealed to raise the pressure in the chamber to a predetermined value above the pressure in said vesicle, increasing the air pressure within said vesicle until it is substantially equal to the air pressure within said chamber, venting said vesicle to the atmosphere to render the pressure in said chamber effective to contract the vesicle to minimum volume, the quantity of air in said chamber remaining constant while the pressure of said air decreases, and then by the use of Boyles law computing the volume of the body being measured from the known volume of the chamber and the pressure therein prior to and after contraction of the vesicle.

13. A method of measuring the volumetric Shrinkage of an irregularly shaped article constructed from fluid pervious fabric comprising disposing a vesicle of relatively thin walled resilient deformable material in said article, enclosing said article and the vesicle supported therein in a sealed chamber of known volume, varying the relative internal pressures as between the vesicle and chamber While they are sealed from each other successively to effect an expansion of the vesicle substantially to the optimum volume of said article and its contraction to minimum volume while the chamber is sealed, noting the pressure in said chamber before and after contraction of the vesicle is effected, computing the volume of the body from the known and recorded data by the use of Boyles law, washing said article to shrink the same, repeating the steps above set forth for determining the volume of said body after shrinkage, and subtracting the volume thus found from the volume prior to washing to determine the shrinkage,

14. A method of measuring the volume of fluid pervious hollow bodies comprising disposing a vesicle of relatively thin walled resilient deformable gas-impermeable material in said body, expanding the vesicle suificiently to expand the body to optimum volume, pressurizing a confined space surrounding said vesicle raising the pressure in said vesicle until it is substantially equal to the pressure within said confined space, venting said vesicle to contract the vesicle and body completely while the quantity of gas in said confined space remains constant, and then computing the volume of the body using Boyles law, the known volume of the confined space, and the pressure in the confined space before and after contraction of the vesicle.

15. A method of measuring the volume of a fluid-pervious hollow collapsible body, comprising disposing a vesicle of relatively thin walled flexible substantially gas-impermeable material in said body, placing said Vesicle and body while collapsed in a chamber of predetermined volume sufficiently large to permit expansion of said body to its natural shape, expanding said vesicle in said body until said body assumes its natural shape, the quantity of gas enclosed in said chamber remaining constant during the foregoing step of expanding said vesicle, noting the respective pressures in said chamber during the state of expansion of said body and during the state of collapse of said body, and computing the volume of said body according to Boyles law from the predetermined volume of said chamber and the respective pressures in said chamber when said body is expanded and collapsed.

16. A device for measuring the volume of a fluid-pervious hollow collapsible body, comprising a vesicle of relatively thin walled flexible substantially gas-impermeable material capable of expanding in response to internal pressure substantially to fill the body to be measured, a sealable chamber to contain said body and the vesicle disposed therein, supporting means for said body and vesicle, including means to anchor said 10 vesicle within said body and to seal said vesicle from said chamber, means communicating with the interior of said vesicle to expand said body so as to assume substantially its natural shape, and means for indicating the pressure within said chamber.

17. A device for measuring the volume of a fluid-pervious hollow collapsible body, comprising a vesicle of relatively thin walled flexible substantially gas-impermeable material capable of expanding in response to internal pressure substantially to fill the body to be measured, a sealable chamber to contain said body and the vesicle disposed therein, supporting means for said body and vesicle, including means to anchor said vesicle within said body and to seal said vesicle from said chamber, means communicating with the interior of said vesicle to expand said body So as to assume substantially its natural shape, means for indicating the pressure within said chamber, and means for indicating the pressure Within said Vesicle.

LOUIS I. WEINER. BENJAMIN PAUL BERMAN.

References Cited in the file of this patent UNITED STATES PATENTS Number Name Date 2,074,832 Dushane Mar. 23, 1937 2,113,686 Gift Apr. 12, 1938 2,285,151 Firestone June 2, 1942 2,304,731 Fairbairn Dec. 8, 1942 2,314,540 Huntington Mar. 23, 1943 

